The present invention relates generally to a vacuum processing system for objects to be processed, such as semiconductor wafers and LCD substrates.
In each process for fabricating semiconductor devices, a load-lock chamber and a transfer chamber are provided for delivering semiconductor wavers serving as objects to be processed, from a clean room to a processing chamber in which a predetermined process is carried out, or for delivering processed semiconductor wafers from the processing chamber to the clean room. The load-lock chamber and the transfer chamber are provided with a transfer system for transferring semiconductor wafers.
That is, conventional vacuum processing systems have a structure wherein a processing chamber, a load-lock chamber and a transfer chamber are interconnected. In view of the prevention of the sacrifice of throughput, it is required to store at least two processed and unprocessed semiconductor wafers in vacuum atmosphere in the load-lock chamber.
As conventional transfer arm mechanisms serving as transfer systems, there are known SCARA (Selective Compliance Assembly Robot Arm) twin pickups types, SCARA dual arm types, flog-leg twin pick types and so forth. All of these mechanisms have a multi-articulated structure which has pivotably connected arms, and have a swivel mechanism on the proximal end side of the arm and a pick on the distal end side for supporting a semiconductor wafer. By the swivel motion of the arm and the bending and stretching motions of the joint portion, the semiconductor wafer is transferred.
However, the above described transfer arms, such as SCARA twin pickups types, SCARA dual arm types and flog-leg twin pick types, have many components and complicated structures and operations, so that the load-lock chamber is enlarged for providing a space, in which the arms are swiveled, to increase costs.
This invention has been made in view of the above described circumstances, and it is an object of the invention to provide a vacuum processing system capable of reducing the size and costs of the system.
In order to accomplish this object, according to the present invention, there is provided a vacuum processing system comprising: a vacuum processing vessel; a load-lock chamber enclosed with a case having a vacuum-side gate valve provided between the chamber and the vacuum processing vessel, and a atmosphere-side gate valve provided on opposite side to the vacuum-side gate valve, the chamber being communicated with an interior of the vacuum processing vessel via the vacuum-side gate valve; a transfer arm, provided in the load-lock chamber, for carrying an object to be processed, in and out of the vacuum processing vessel; and first and second buffers, provided in the load-lock chamber, for temporarily supporting thereon the object, wherein the first buffer is arranged on a side of the vessel, and the second buffer is arranged on a side of the vacuum-side gate valve, and the transfer arm has an arm portion capable of bending and stretching, and a supporting portion for supporting thereon the object, the supporting portion linearly moving along a linearly-moving route passing through the first and second buffers, while maintaining an attitude of the supporting portion, in accordance with bending and stretching of the arm portion.
According to such a vacuum processing system, the object supported on the supporting portion of the transfer arm can be carried in and out if only the arm portion bends and stretches, so that the structure and operation of the transfer arm can be simplified. It is not required to swivel the transfer arm, so that the load-lock chamber can be miniaturized. Therefore, the costs of the vacuum processing system can be lower than those of conventional systems.
The arm portion of the transfer arm may comprise: a swivel driving shaft; a driving-side swivel arm having a proximal end portion, which is fixed to the swivel driving shaft, and a distal end portion; a driven-side swivel arm having a proximal end portion, which is rotatably connected to the distal end portion of the driving-side swivel arm via a swivel driven shaft, and a distal end portion to which the supporting portion is rotatably connected via a joint shaft; and power transmitting members provided between the swivel driving shaft and the swivel driven shaft and between the swivel driven shaft and the joint shaft, respectively.
In the load-lock chamber, the first buffer may be arranged on a side of the vacuum processing vessel and the second buffer may be arranged on an opposite side to the vacuum processing vessel, and a pre-alignment mechanism may be provided below the first buffer.
A pre-alignment mechanism may be provided on any one of the first and second buffers.
According to these vacuum processing systems, the object to be processed can be pre-aligned by the pre-alignment mechanism before the object is carried in the vacuum processing vessel.
The supporting portion of the transfer arm may comprise a pair of picks capable of taking an open position and a closed position, the picks supporting the bottom face of the object in the closed position, and releasing the object in the open position.
According to such a vacuum processing system, by opening and closing the pair of picks of the transfer arm, the object to be processed can be delivered without causing the arm portion to bend and stretch.
The first and second buffers may be provided so that objects to be processed, each of which is supported on a corresponding one of the first and second buffers, overlap with each other viewed from top or bottom.
The supporting portion of the transfer arm may have an upper supporting portion and a lower supporting portion, each of which is capable of supporting thereon the object, the upper supporting portion and the lower supporting portion being offset from each other in the directions of the linear movement of the supporting portion. In that case, the supporting portion of the transfer arm may function as at least one of the first and second buffers.
According to these vacuum processing systems, each of objects to be processed is supported on a corresponding one of the upper supporting portion and the lower supporting portion which are offset from each other. Therefore, it is possible to further simplify the structure than a structure that two supporting portions are independently moved, and it is possible to reduce the operation of the transfer arm.